Birder's Journal: This Warbler Is a Master of Deception
for National Geographic News
|August 29, 2002|
A favorite trail of mine runs for five miles along the west side of the
largest reservoir in the county. I suppose I've hiked sections of it a
thousand times, but the odd sensation that brought my gaze to my feet
one summer afternoon was something new.
A worm-eating warbler had flapped across my path, grazing my boot with its wings. Now it was fluttering along the forest floor and chipping nervously, behavior that meant it probably had a nest nearby.
Worm-eating warblers nest on the ground, and they defend their eggs or young by trying to lure predators away. Although tempted to search for the nest, I gave the area only a cursory look. Even with a good clue like this, nest-finding requires patience. I wanted to get back into the rhythm of walking, and let the warbler, probably an incubating female, get back to her eggs.
Returning along this stretch of trail a half-hour later, I had forgotten the warbler, until she cut me off again. She squeezed under my right boot just before it hit the ground. This time, I concentrated on where she first appeared and found the nest almost immediately. It was tucked into the side of a leafy knoll, just two feet off the trail.
Next to a rock, and overhung with a shelf of fallen leaves, the nest contained four tiny whitish eggs flecked with brown. Although I had never found a worm-eating warbler nest, I quickly moved on. Every second I lingered exposed the eggs to danger and kept the female from incubating.
I had not touched the nest. It would have been a death sentence for the eggs, because the scent of a human, often leading to food, attracts predators.
Even my innocent pause put a worrisome glitch in my scent trail. Hours later, a rapacious raccoon foraging in the darkness might know I had stopped. Its suspicions raised, it could start sniffing around and find the nest.
As I headed back to the car, I wondered how worm-eating warblers survive when they build their nest on the ground, so vulnerable to predators.
Walking the same trail a few days later, I had trouble finding the nest, though I had made careful note of nearby landmarks. But I was still looking for the whitish eggs. Soon I realized that where the eggs had been, there were now four nestlings. Covered in brownish-gray down, they blended into the shadow of the overhanging leaves.
The baby birds huddled together, quiet and motionless. The mother flew off as usual but seemed no more agitated than she had been when guarding the eggs. I kept this visit even briefer than the first.
More than a week had passed by the time I checked the warblers again. The nest was empty and intact, and I was relieved to find no signs of disaster: blood, feathers, or other remains. Surely a raiding raccoon would have dislodged the fine grasslike stems resting on the nest's front rim.
One thing did bother me: the silence. If the nestlings fledged, where had they gone? A few minutes' walk from the nest, just as I was accepting the worst, I flushed a juvenile worm-eating warbler from the side of the trail.
Flapping furiously but moving slowly, it rose into the air and made a precarious landing in a sapling a few feet away. An adult then flew in quickly and gracefully, chipping at me in anger. Stubby-tailed and plump-looking, the young bird was mostly pale yellow, its crown showing just a hint of the bold dark stripes that distinguish the adult. Consistent with my noninterference policy, I kept going. On my return, I saw two young birds and an adult.
Unlike the open deciduous woods around the nest, this rocky slope offered plenty of cover. If danger approached, the awkward-flying young had mountain laurel thickets and a spattering of hemlocks in which to hide.
I can't prove these warblers were from the nest I had found, but I believe they were. The young were the right age, and on subsequent walks I would see a family of three or more worm-eating warblers within 100 yards of the nest.
They were lucky birds, I thought, but on reflection I realized this was underestimating them. Like the thief in Edgar Allan Poe's Purloined Letter, the adult female I had almost stepped on was a master of the art of deception. She had placed her well-camouflaged nest "immediately beneath the nose of the whole world, by way of best preventing any portion of that world from perceiving it"a survival strategy that protected her eggs through 13 days of incubation, and her nestlings until they fledged 10 days later.
Robert Winkler's book of essays on his adventures with birds of the "suburban wilderness" will be published in 2003 by National Geographic Books.
Recent Bird Stories by National Geographic News
Bald Eagles' Manhattan Return Turns Turbulent
Birders Journal: Attack of the Flying Goshawk
Saving the Edible-Nest Swiftlet
Birder's Journal: Seduced by Dueling Thrushes
Birds Can Be Picky About Their Neighborhood, Studies Find
Acid Rain May Have a Role in the Decline of the Wood Thrush
Icelandic Kids Save Befuddled Puffins
Crow Makes Wire Hook to Get Food
Rare Warbler Eluding Extinction in U.S.
In India, Nets Save Baby Storks From Falls
Bald Eagle Bounces Back After Decades of Persecution
Birder's Journal: It's Survey Season for Breeding Birds
Conservationists Fight to Save Harpy Eagles
Birder's Journal: Chasing Down Warblers
Africa's New Safari Trend Is for the Birds
Decline of Red-Tailed Hawks Has U.S. Scientists Puzzled
A Reason to Give Thanks: The Return of the Wild Turkey
State Bird of Hawaii Unmasked as Canadian
Harry Potter Owl Scenes Alarm Animal Advocates
Ultrarare Woodpecker Spurs Ultimate Birding Trip
"Extinct" Woodpecker Still Elusive, But Signs Are Good
Extinct Dodo Related to Pigeons, DNA Shows
Bird Extinctions May Hold Clues to Human Survival, Author Says
Tagging Hobbles Penguins, Some Researchers in Cape Town Contend
Patagonia Penguins Make a Comeback
Penguin Decline in Antarctica Linked With Climate Change
Ice Buildup Hampers Penguin Breeding in Antarctica
Evolutionary Oddities: Duck Sex Organ, Lizard Tongue
Some Ducks Let Young Be Raised by Relatives
Turkey Vultures Flourish in the U.S. Thanks to Road Kill
Forecasting the Journey South
National Geographic Bird Resources
Bald Eagles: Come Back From the Brink
Experience the Sights and Sounds of Eagles
Nationalgeographic.com Bird-Watching Sites
Florida Keys Area
Maine's Acadia National Park
New Orleans Area
New York City Area
North Carolina's Outer Banks
Rocky Mountain National Park
Salt Lake City Area
San Francisco Area
Santa Fe Area
South Dakota's Black Hills
Washington's Olympic National Park
Wyoming's Grand Teton National Park
Yellowstone National Park
Yosemite National Park
From the National Geographic Store
Guide to North American Birds
Portable Birdsong Identifier
|© 1996-2008 National Geographic Society. All rights reserved.|